Orthodontic therapy has the object of aligning and repositioning teeth for both functional and aesthetic purposes. This is achieved by the use of a variety of orthodontic appliances including, brackets, wires (arch wires), coil springs and elastics. In combination, these appliances are fixed to teeth in such manner that orthodontic forces and moments cause the teeth to move in the desired direction.
There are currently acceptable guidelines in orthodontics, which define the optimal dental and skeletal relations which should be the goal of the orthodontic treatment. A summary of such guidelines can be found in Straight Wire, the Concept and Appliances, by Laurence F Andrews, L.A. Well, Co., San Diego, Calif., USA, 1989. These guidelines are based on both functional and aesthetic considerations.
A common problem in the orthodontic field is the lack of space in the dental arch called dental crowding. In this clinical situation the orthodontist should decide if his orthodontic treatment plan will include the solution of tooth extractions (which is an irreversible procedure), how teeth should be moved against anchorage units during the treatment protocol and accordingly what orthodontic appliances should be chosen and how to apply them on the teeth to achieve a desired outcome. The procedure of assessing the best treatment plan by the orthodontist is typically based on patient clinical measurements, plaster cast and radiographic analysis, the orthodontist's personal “look and feel”, and his prior experience and skills. In some cases it also required to prepare wax-based diagnostic setup model which exhibits the possible end result of the orthodontic case. This approach is time consuming and also does not permit to easily visualize the outcome of several treatment options at the same time.
There is accordingly a need in the art to provide the orthodontist with a tool which enables him to design the treatment procedure—which will yield an optimal outcome, and to analyze possible outcome of different treatment methods.
PCT Application WO 99/34747 describes a method for virtual orthodontic treatment, which utilizes a virtual set of orthodontic components, in a virtual computerized environment. A set of rules, which are mainly geometric rules, are applied to move the teeth by the use of standard and non standard virtual orthodontic components.